Comprehensive studies of non-covalent interactions within four new Cu(ii) supramolecules

Abstract

This work investigates the supramolecular aggregation of Cu(II) complexes based on a combination of the heterocyclic N-donor ligand 2-aminopyrimidine (2-apym) and a variety of different carboxylate ligands, like salicylic acid (H 2 SAL), maleic acid (H 2 MAL), and glycine (HGLY). Four new Cu(II) complexes [Cu(HSAL) 2 (2-apym) 2 ] (I), [Cu(HSAL) 2 (2-apym) 2 ]?(H 2 SAL) 2 (2-apym) (I9), {(H2apym)[Cu(GLY)(m-Cl) 2 Cl]} n (II) and [Cu(m-MAL)(2-apym)] n (III) have been synthesized and characterized by elemental analyses, FT-IR spectra, and X-ray structural analyses. I and I9 appear as molecular clusters whereas II is a 1-D coordination polymer with weak axial Cu-Cl interactions. However the last one shows a 2-D coordination polymer with trigonal bipyramidal geometry for Cu(II) ion. The two last cases have no molecular fragments packed with non-covalent interactions. In these new supramolecular compounds, existent species join together with the cooperation of multiple inter/intra-molecular classical O-H … O/N, N-H … O/N, and non-classical N-H … Cl hydrogen bonds (H-bonds), offset face to face p … p, edge to face C/N-H … p, and lp … p stacking interactions in the form of various homo/hetero-synthons leading to architecturally different structures. DFT calculations were used to estimate the binding energy of the involved non-covalent interactions and whole stabilization energy of related network of I, I9, and II. Theoretical calculations facilitate the comparison of intermolecular interactions, which demonstrate that for all of I-II, N-H … N and N-H … O H-bonds govern the network formation. The equilibrium constants for the three protontransfer systems including SAL/2-apym, GLY/2-apym, MAL/2-apym, the stoichiometry and stability of complexation of these systems with Cu 2+ ion in aqueous solution were investigated by potentiometric pH titration method. The stoichiometries of the most complex species in solution was compared to the crystalline Cu 2+ ion complexes with the cited proton-transfer systems.

Biochemical Capacitance of Geobacter Sulfurreducens Biofilms

“…A central part of crystal engineering employs synthons‐recognition events for the directed assembly of discrete or extended supra‐molecular architecture 14. Hydrogen bonds have become a reliable non‐covalent interactive tool in the construction of supramolecular architectures 15.…”

Evaluation of Non‐covalent Binding Energies and Optoelectronic Properties of New CuBr2(C6H7N)2 Complex: DFT Approaches

“…Negatively computed of network stabilization energy (nfe) ( E nfe = E network – nE monomer ), indicates that these interactions could form the network favorably (see Table ). This strategy has been successfully applied in further works by some of us , , . However, the related fragments ( 1 ‐ frag1 , 1 ‐ frag2 , and 1 ‐ frag3 , see Figure ) and 1 ‐ net are optimized and in the following the respective interactions and their probable interplaying effect are studied ( via the mentioned procedure; see computational details).…”

“…In type A it treats both as Lewis base and acid simultaneously, therefore both HBs should be reinforced. In types B and C, simultaneously in both HBs, the atom acts respectively as a Lewis acid (D) and base (A) which causes of their weakening (see Scheme ) , , …”

“…A very promising approach entails a combination of DFT‐D (dispersion energy corrected) with a GGA functional (like B3LYP) and a medium basis set . This technique is a very promising tool for studies of the dynamic properties of small and medium non‐covalent complexes . The full‐potential linearized augmented plane wave (FP‐LAPW) method using Perdew‐Burke‐Ernzerhof generalized gradient approximation (GGA) is one of the new interesting DFT methods for total energy calculations .…”

Synthesis, structure, solution and DFT studies of a pyrazine-bridged binuclear Cu(II) complex: On the importance of noncovalent interactions in the formation of crystalline network

“…Noncovalent interactions, such as hydrogen bonds, r-hole bonds, electrostatic as well as metal ion coordination, represent the backbone of self-assembly processes and supramolecular architectures [34][35][36][37]. Hydrogen bonding still remains the most important interaction to control organization in the solid state.…”